In an electrostatic fluidized bed a moving grounded wire or other elongated member is coated with a cloud of charged resin particles which forms above the level of the fluidized powder. The wire then moves into an oven where the particles are fused.
A recent development has been to position a vacuum chamber on each side of the bed to draw air from the inside of the bed, thereby controlling the position of the cloud of particles around the wire. The purpose of this arrangement was to provide a uniform cloud and therefore a uniform coating on the wire. The vacuum chambers were provided with dampers for controlling the amount of vacuum.